Questions about the health benefits of vitamin supplements have been percolating in the medical establishment for decades — even as the multivitamin industry has grown to a multi-billion powerhouse in the U.S. This week, the respected journal the Annals of Internal Medicineput its well-heeled foot down.

"We believe that the case is closed — supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful," the journal said in an editorial. "These vitamins should not be used for chronic disease prevention. Enough is enough."

Here's Dr. Edgar Miller of Johns Hopkins Bloomberg School of Public Health, one of the editorial's five co-authors: "What will protect you is if you spend the money on fruits, vegetables, nuts, beans, low fat dairy, things like that," Miller tells CBS News. "Exercising would probably be a better use of the money." The only exceptions are folic acid for pregnant women and, possibly, vitamin D — the studies are mixed on its benefits and risks.

Assuming Miller and his colleagues are right — and they base their assertion on three large, recent studies — Americans have been wasting lots of money on vitamins. About half of U.S. adults take dietary supplements, and the vitamin industry has grown to $12 billion a year for vitamins alone and about $30 billion for all dietary supplements. That's just in the U.S.

How did the vitamin industry convince Americans that they need to bulk up on vitamin A, vitamin C, various forms of vitamin B, and other vitamins or multivitamin supplements? "Vitamin manufacturers argue that a regular diet doesn't contain enough vitamins, and that more is better," and most people wrongly assume that "at the very least, excess vitamins can't do any harm," Paul Offit, an infectious disease specialist at Children's Hospital of Philadelphia, said in The New York Times in June.

But much of the blame lies with a flawed genius, Linus Pauling, Offit says. Pauling, the father of molecular biology and near-discoverer of DNA, was "so spectacularly right that he won two Nobel prizes and so spectacularly wrong that he was arguably the world's greatest quack," Offit wrote in The Guardian. Starting in 1966, Pauling started evangelizing about the wonders of vitamin C, making outrageous claims about its salutary effects.

In 1970, Pauling published a bestseller, Vitamin C And The Common Cold, arguing that 3,000 mg of the vitamin each day would eradicate the cold. He went on to insist that a multitude of vitamins, including A, E, and beta-carotine could treat or cure a whole host of maladies, from cancer to AIDS. Study after study after study proved him wrong.

Pauling really believed his claims, but the vitamin industry had more cynical motives: Money, as Offit recounted in The New York Times. The Food and Drug Administration proposed regulating vitamin supplements containing more than 150 percent of the recommended daily allowance in December 1972, meaning "vitamin makers would now have to prove that these 'megavitamins' were safe before selling them," Offit continues:

Not surprisingly, the vitamin industry saw this as a threat, and set out to destroy the bill. In the end, it did far more than that. Industry executives recruited William Proxmire, a Democratic senator from Wisconsin, to introduce a bill preventing the FDA. from regulating megavitamins.... Proxmire's bill passed by a vote of 81 to 10. In 1976, it became law. Decades later, Peter Barton Hutt, chief counsel to the FDA, wrote that "it was the most humiliating defeat" in the agency’s history. [New York Times]

So, thanks to Linus Pauling, money, and politics, Offit concludes, "consumers don't know that taking megavitamins could increase their risk of cancer and heart disease and shorten their lives."

But surely consumers play some role in the rise of the vitamin industrial complex. Research about the ineffectiveness of vitamins, or worse, has been around since the 1940s, after all. "People over time and particularly people in the United States have been led to believe that vitamin and mineral supplements will make them healthier, and they're looking for a magic pill," Dr. Cynthia Mulrow, another of the Annals of Internal Medicine editorialists, tells Reuters.

And the "magic pill" habit may be hard to break, scathing editorial or no. For what it's worth, here's the pushback from the supplement trade group the Council for Responsible Nutrition:

The Annals of Internal Medicine editorial "demonstrates a close-minded, one-sided approach that attempts to dismiss even the proven benefits of vitamins and minerals," says the group's CEO, Steve Mister. "It's a shame for consumers that the authors refuse to recognize the real-life need for vitamin and mineral supplementation, living in a fairy-tale world that makes the inaccurate assumption that we're all eating healthy diets and getting everything we need from food alone."

At the end of this CBS News report, the featured inveterate vitamin-taker buys the industry's argument and declares that, despite the evidence and her healthy diet, she will continue taking vitamins. She almost certainly isn't alone: